RAK19007 Grid Board low-profile Mount

This is to adapt a RAK 19007 WisBlock to the 5mm pitch grid boards found inside waterproof electronics enclosures, without using up too much extra space. It uses 4 m2x6 plastic screws to mount the RAK to the adapter, and four M3x8 CSK screws to mount to the grid board. The best screws to use are the type specifically for screwing into plastic (semi self-tapping), rather than regular machine screws. It's a bit tedious to remove, as you first have to unscrew the RAK from the adapter before removing the adapter from the grid board, but it makes up for that in footprint reduction.